Sometimes when you use a certain port, you will find that the port is occupied, but you don't know which program is occupied. You can check the port usage through the following command.
Windows
1, netstat -aon|findstr "xxx" xxxx- is the port number
2, tasklist|findstr "yyyy" yyyy is the ID number of the process using the port
Linux
1, netstat -anp|grep "xxxx" xxxx- is the port number
